Machine for making insulating elements.



C. H. IHORDARSUN.

MACHINE FOR MAKING INSULATING ELEMENTS.

APPLICATION FILED MAR. 20, I9I5.

Patented Mar. 27, 1917.

3SHEETSSHEET I.

W 0 n w m, H V PM h! 6 14/7; Yin/856s:

Thordmsw (I I 7). z

C. H. THORDARSON.

MACHINE FOR MAKING INSULATING ELEMENTS.

AFPLICATION FILED MAR.20. I915.

3 SHEETSSHEET 2.

6 hmier'fl. 17am! (17 15014 C. H. THORDARSON.

MACHINE FOR MAKING iNSULATING'ELEMENTS.

APPLICATION FILED MAR. 20, 1915.

LQQSYE Patented Mar. 27, 191?.

3 SHEETS-SHEET 3.

CHESTER H.

MACHINE FOR MAKING INSULATING ELEMENTS.

Application filed March 20, 1915.

To all whom it may concern:

Be it known that I, Cmss'rnn H. Tnoamasox, a citizen of the UnitedStates, and a resident of Chicago, in the county of (ook and State ofIllinois, have invented certain new and useful Improvements in Machinesfor Making Insulating Elements; and I do hereby declare that thefollowing is a full, clear, andeXa-ct-description thereof, referencebeing had to the accompanying drawings, and to the characters ofreference marked thereon, which form a part of this specification.

This invention relates to a machine for making insulating elementscomposed of a plurality of superposed turns or sheets of insulatingmaterial which are impregnatedwith a flowable insulating compound duringthe winding or laying on operation and are insulatedly separated by athin film of said compound. 7 a

Such an insulating element and the machine for making same are shown inmy prior application for U. S. Letters Patent, Serial No. 833,182, filedon the 20th day of April, 1914, and the invention herein disclosedconstitutes an improvement on the invention shown in my priorapplication.

Among the objects of the invention is to provide a machine forassembling such insulating elements, whether-the same have the form of atube or are flat, in the presence of a high vacuum so that air and othergases are to a maximum degree withdrawn from the body of the inaterialfrom which the in-, sulating element is formed and from'between thelayers of said material.

A further object of the invention is to provide a machine of thischaracter in which the winding or laying on mechanism, with its powerplant, constitutes a unitary mechanism which may, as a whole, be readilyre moved from and inserted into the air tight compartment or tank whichincloses said mechanism.

A further object of the invention is to provide means whereby the sheetwhich is being assembled into the insulating element may be cut when thedesired number of layers areassembled and whereby the vac-- uum or lowpressure may be in any suitable manner released. and whereby theassembling mechanism may be continued in opera-- tion after such vacuumrelease to prevent the entrance of air under normal pressure be-Specification of Letters Patent.

"vacuum is maintained in the tank.

THORIDARSON, OF CHICAGO, ILLINOIS.

Patented Mar. 27, 917.

Serial No. 15,930.

tween the layers of the insulating material which compose theinsulatingelement. at the ends of the latter, the insulating element forthis purpose being rotated in the flowable insulating compound untilsufficiently cooled to prevent the entrance of air between said layers.

A further object of the invention is to provide means for subjecting thesheet to the effects of a high tension electro-sta'tic discharge justprior to the laying of the sheet on the insulating element so as tothereby further drive out air. 'ases, water and other deleteriousforeign matter from the sheet.

A further object of the invention is to provide in a machine of thischaracter means for scraping the excess insulating compound from theface of the sheet prior to the assembling of the sheet in the insulatingelement, and for maintaining the scraping device sufliciently heated torender the scraping operation efficient.

Other objects of the invention are to simplify and improve machines ofthis general character. and the invention consists in the mattershereinafter set forth and more particularly pointed out in the appendedclaims.

In the drawings Figure 1 is a horizontal section of a machine embodyingmy invention.

Fig. 2 is an end view thereof, showing the inclosing tank in section.

Fig. 3 is a top plan view of a portion of the winding mechanism and theshearing mechanism.

Fig. 4 is a vertical section on the line 44 of Fig. 5.

Fig. 5 is a front elevation of a portion of the winding mechanism andthe scraping and shearing mechanisms.

Fig. 6 is a side view of the machine. partially broken away, showing thewinding mechanism partly withdrawn from the in closing tank.

As shown in the drawings. 10 designates an air tight tank, preferablycircular in cross section, provided with a fixed end wall 11 and aremovable end wall 12, the latter being attached to the tank wall bymeans providing an air tight joint. The said tank is adapted to beconnected by a suitable hose or pipe 13 with a vacuum pump 14 or othersource of low pressure whereby a high The said tank is supported in itshorizontal position by means of suitable horizontal supporting members16 attached thereto at the sides of its center. It is provided withinternal tracks 17, 17 which extend from end to end of the tank and onwhich the winding mechanism. hereinafter to be described, is normallysupported. The said winding mechanism is adapted to be withdrawnoutwardly onto supplemental tracks 18. ar ranged in cndwise extension ofthe tank tracks and which may be temporarily connected to the tanktracks when the end wall 12 is removed.

The winding mechanism is a power driven, self contained machine. Itcomprises, in general terms, a frame composed of rigidly connectedupright and horizontal members 20. 21, respectively. Extending acrossthe said frame at the lower side thereof are axles .22 which carrysupporting wheels 23, that rest and roll on the tracks 17 and 18. \Vhenthe whaling mechanism is run out onto the supplemental tracks 18 freeaccess may be had thereto to remove a wound tube there from or to applya new reel of sheet material thereto and to thread it through theguiding and winding elements.

I The tube may be wound upon any suitable mandrel '25, as for instance,the collapsible mandrel shown in my aforesaid prior application. Theshaft 26 of said mandrel is rotatively mounted in suitable dividedbearings supported on the frame in the mannershown in Fig. 2, wherebythe mandrel and the wound tube may be readily removed from the machineand another mandrel applied thereto. The mandrel is herein shown asdriven by a motor 28 supported on the frame and is connected through themedium of a worm 29 to a worm wheel 30 that is fixed to one endof themandrel shaft. Any other suitable drive may of course be employed.

designates a rotative reel, the shaft 33 of which is mounted in bearings34 carried by the upright members of the frame at one side thereof. Saidreel receives a roll A of sheet material which is unwound to produce theinsulating element. The sheet a is carried from the reel over a. guideroller 35 mounted in an extension 36 of the frame, thence downwardlyinto a receptacle 38 which contains a flowable insulating compound orbath by which the sheet is to be impregnated. The sheet is guidedthrough said insulating bath about guide rollers 40, 41, the shafts ofwhich are rotativelymounted in-the end walls of the tank. It iscontinued from the roller ll upwardly over a roller 43 which, in thepresent instance, is a metal roller and constitutes one of theelectrodes of a high tension current circuit, and from said roller 43the 'sheetis wound upon the mandrel 25. The bearings for the roller T3are carried by insulators 45 which are supported by the upper ends ofswinging arms 46 that are pivoted at their lower ends at 47 to themachine frame and swing at their upper ends toward and away from thetube winding mandrel. At the line at which the sheet is laid on themandrel or the form-, ing tube thereon there is provided an ironing orpressing roller 48 which presses the sheet closely upon the forming tubein a manner similar to that shown in my aforesaid prior application. Ifdesired, a suitable tension device may be applied to the roll or thereel 32 so as to prevent too free unwinding of the sheet from the roll.The said tension device may be like that shown in my aforesaid priorappliration. or it may consist of a weighted bar 50 which lies upon theroll and is connected to the machine frame by resilient arms 51. I

The ironing roller 4:8 is mounted in the upper ends of the said swingingarms 46. As herein shown the said swinging arms ex tend above the levelof the top of the insulating bath tank 38 and are provided with inwardlyand downwardly extending members 52 which extend over the top edges ofthe end walls of the tank and support the shaft of the roller 48. Saidroller 48 may be pressed toward the forming tube on the mandrel byspring pressure device which consists, in the present instance, ofsprings 55 attached at their rear ends to the swinging arms 46 and areconnected at their forward ends by means of links 56 to hand levers 57that are pivotally connected at their lower ends to the frame. Said handlevers may be locked in any suitable manner to ratchets 58 carried bythe frame and engaging the upper ends of said levers. The hand leversand ratchets provide means whereby spring pressure of the roller 48against the forming tube may be varied.

Between the rollers 43 and 48 the sheet is subjected to a scrapingoperation to remove surplus insulating compound therefrom. The saidscraping operation is herein shown as effected by, means of thesharpened edges of upper and low-er scraper bars 60, (31, respectively,which extend between and are attached in any suitable manner to theupper ends of the swinging arms. 46. The. said scraping bars are shownas of angular cross section. one edge of each bar being sharpened toconstitute a scraping edge. In the present instance. the scraping edgeof the lower bar is formed at the lower edge of the vertical memberthereof and contacts with the outer surface of the sheet. The sheetpasses across said scraping edge and along the vertical member of thebar and engages at itsinner-side the scraping edge formed on thehorizontal member of'the upper bar 60.

Preferably the upper and lower scraper bars are equipped with suitableheating elements 68, 66, respectively, which may consist of thin stripsof metalof lowelectri cal resistance insulated in any suitablemanner'fron i the bars, as by being inclosed in envelops of insulatingmaterial. The heating of the bars prevents hardening of congealing ofthe insulating compound on the sheet to such extent as would-render itsremoval therefrom by the scraper bars in flicient. Desirably also theroller 41in the tank at the rising side of the sheet is also providedwith a low resistance element, indicated at 66; so as to assist inmaintaining the insulating compound at the desired degree of fluidity.

The main or principal source of heat-to heat the insulating compound inthe tank 38 may be'of any suitable or preferred character such as theburner pipes 67 arranged below the tank and supported in any suitablemanner and connected with an external source of fuel supply by means ofa suitably located supply pipe or hose. 'As additional means ofmaintaining the compound suitably warm lt may provide the tank with oneor more internal heating elements-67, one being herein shown. -The saidheating elements of the scraper bars, the guide roller 4-1 and theheating element 67 maybe connected with a suitable source of electricalenergy in multiple in the manner indicated in Fig. 5 and more fullydisclosed inmy companion application for U. S. Letters Patent. filed onthe 20th day of March. 1915, Serial No. 15,929, suitable switches beingincluded in the circuits to permit them to be separately controlled asfound necessary or desirable. I

The electriemotor 28 is fed from a suitable source of supply through aconductor 70 which leads through an outlet plug in the tank wall, notherein shown. Preferably the tank is provided with a plurality ofinternal lamps 71 to illuminate the winding mechanism. The said lampsmay be supported on the tank wall oron the frame, as desired, and. thelamp circuit may be connected with the motor circuit in the mannerindicated in my aforesaid companion application.- when so equipped withilluminating lamps the tank will be provided with one of more windows 73through which the operation of the winding mechanism may be observed. 7

In order that the sheet may be readily severed at-the time sufficientnumber of turns or layers have been wound into the tube to provide therequired thickness of the tube wall, I have provided a shearingmechanism, with means for automaticallyoperating it, to sever the sheet.Said shearing mecha nism may be located either at the rising. ordescending side 0f.the sheet. As herein shown it is'lo'cated at therising side of the sheet between the insulating bath and the windingmandrel or form. It comprises a from the wound tube through which thesheet passes. The movable blade is swung into its shearing position anoperating spring 78 which is con nected to the free end of said bladeand to a fixed part of the machine. Said movable blade is held in itsnormally retracted position by means of a pivoted latch 79 that isprovided with a tooth which engages-a stud 80 carried by the swinging orfree end of the blade. The heel end of the latch is formed to constitutean armature 81 which cooperates with the core of an electro-magnet 82.the arrangement being such that when the said magnet is energized thearmature is drawn toward said core to release the latch from the pin orstud 80 and to thereby permit the spring 78 to swing the movable bladeinto its cutting position. The

winding of said electroanagnet 82 may be connected in the motor circuitin the general manner illustrated in my aforesaid companion application.

After the sheet has been severed by the shearing mechanism described.the end wall 12 of the tank is removed and the winding and insulatingmechanisms are withdrawn from the tank 10 out onto the supplementaltracks 18. The connections of the various circuit wires of the internalterminals, and the connection of the supply pipe to the gas burners issuch as to permit the mechanism to bethus withdrawn withoutdisconnecting the terminals and gas supply pipe. The opening of the tankreleases the vacuum and raises the pressure thereon to atmosphericpressure. In order to prevent air leaking into the spaces between theturns or convolutions of the wound tube at the ends thereof after therelease of the vacuum. the rotation of the finished tube may becontinued for a period while it is subjected to the drying influence ofa fan or other suitable drying means. The application of heat to theinsulating compound may be also continued so as to maintain saidcompound in a suitable liquid or flowable state. Thus the liquidinsulating compound within the receptacle seals the interspaces betweenthe layers or convolutions of the tube at the ends of the latter andprevents leakage of air therebetween. The same general results withrespect to the release of the vacuum maybe effected within the tank 10before the winding mechanism is withdrawn therefrom after the sheet issevered by the shearing mechanism by conlutions of the said tube.However. the with-.

draWal of the tube with the winding meching the further setting 'orhardening of the tube in the manner described in my aforesaidapplication. Serial No. 833,182. It will be understood that the tube maybe wound on a cylindric mandrel instead of the rectangular mandrelherein indicated.

The roller or electrode 43 is connected to a source of high tensionpulsating direct current through the means of a conductor 90 which maybe connected to the rotating trunnion of the said roller in any suitableman ner, said conductor being insulated from the tank by an insulator91. The conductor 90 is attached to one end of the roller or electrode43 and the circuit is open at the other end thereof. One or both of thescraper bars, or other metal parts of the frame, is grounded so thatthere is set up between said electrode +13 and said grounded metallicportion of the machine an electro-static discharge that has the effectof driving out moisture, air, gases and other deleterious foreignsubstances from the sheet. In this manner the sheet, while beingthoroughly impregnated with the insulating compound, is free fromdeleterious foreign substances such as would decrease its insulatingefficiency. Thus the tube produced posseses uniform insulating qualitiesthroughout the areathereof.

After the tube and the mandrel have been removed from the frame, anothermandrel or the same mandrel, is applied thereto and another sheet orroll of paper is applied to the frame and the leading edge thereof isthreaded through the guiding rollers and at tached to the mandrel.Thereafter the mechanism thus equipped is pushed into the tank and theend wall 12 is fastened thereto, whereupon the operation of winding anew tube is begun.

It will be observed that the sheet or web a is directed from the roll Aover the roll 35't0 the insulating compound bath. This length ofexposure, when operating under a partial vacuum, serves to free thesheet or web from free air and gases, so that the sheet enters the bathwith the pores open to receive the insulating compound. Thereby thesheet becomes impregnated with a larger percentage of the compound thanif the process were carried on under atmospherie pressure. It will befurthermore observed that the sheet is directed from the insulating bathto the forming mandrel over.

directing rollers which exert no compressive or squeezing action on thesheet, so that all of the insulating compound which is taken up by thebody of the sheet remains therein withdrawal of the free air and gasesand the substitution of the insulating compound increases the dielectricquality of the sheet and of the tube resulting from the assemblage ofthe sheet layers. The scrapers across which the sheet passes between theinsulating compound bath and the mandrel are designed only to removesurplus insulating material from the surface of the sheet and to removeair globules or free water which may adhere to said surface.

It will be understood that the structural details of the machine arecapable of variations within the spirit and scope of the invention, andthat the invention is not limited to the structural details shown exceptas herein made the subject of specific claims and as imposed by theprior art.

I claim as my invention I 1. A machine for the purpose set forthcomprising an airtight tank with means to produce and maintain a vacuumtherein during the impregnation and assembling operation, mechanismwithin the tank for assembling thin sheets to constitute a multi-plyinsulating element, means to apply pressure to the sheet as the layersare assembled in the element, means for impregnating the sheets with aninsulating compound prior to the assembling operation and means wherebythe sheet is subjected uniformly in all its parts to the action of thevacuum before it is impregnated.

2. A machine for the purpose set forth comprising an air tight tank withmeans to produce and maintain a vacuum therein during the ii'upregnatingoperation, and a tube winding mechanism embracing a rotating mandrel,means to support a roll of sheet material'within the tank, means to windit on said mandrel, means to' apply pressure to the sheet as it is woundupon the mandrel, and a receptacle for a liquid insulating compoundthrough which the sheet is passed on its way to said mandrel, the rollsupporting means being exterior to said receptacle.

3. A machine for the purpose set forth comprising a receptacle tocontain an insulating compound, a mandrel rotatable in the insulatingcompound in said receptacle, a reel to receive an insulating sheet roll,means to guide the sheet from said roll through the insulating compoundin said receptacle to said mandrel, scraping means between the saidreceptacle and said mandrel to scrape excessive insulating compound fromsaid sheet, and means to heat said scraping means.

4 A machine for the purpose set forth for a liquid lating compound, amandrel rotatable in the insulating compound in said receptacle, a reelto receive an insulating sheet roll, means to guide the sheet from saidroll through the insulating compound in said receptacle to said mandrel,scraping means between the said receptacle and said mandrel to scrapeexcessive insulating compound from said sheet, means to heat saidscraping means and means between said scraping means and said mandrel tosubject said sheet to the influence of a high tension electro-staticdischarge, for the purpose set forth.

5. A machine for the purpose set forth comprising an air tight tank withmeans to produce and maintain a vacuum therein, and a tube windingmechanism embracing a rotating mandrel, means to support a roll of sheetmaterial within said tank, means to wind it on said mandrel, areceptacle insulating compound through which the sheet is passed on itsway to said mandrel, scraper devices to engage said sheet to scrapeexcess insulating compound therefrom and means for heating said scraperdevices.

6. A machine for the comprising an air tight tank, with means to produceand maintain a vacuum therein, a tube winding mechanism within the tankembracing a rotative mandrel with means to direct an impregnated sheetthereto, cutting means adjacent to and parallel with the mandrel tosever the sheet and actuating means for the cutting means operatablefrom a point exterior to the tank.

7. A machine for the purpose set forth comprising an air tight tankwithmeans to produce and maintain a vacuum therein, and a tube windingmechanism in the tank embracing a rotative mandrel, said tank having aself-contained motor driving means, means to support a roll of sheetmaterial in the tank, means to wind it on said mandrel, a. receptacle tocontain an insulating compound through which the sheet is passed on itsway to the mandrel, means to release the vacuum within the tank, andshearing means to sever the sheet while in the tank.

8. A machine for the purpose set forth comprising anair tight tankprovided with a removable closure, means to produce and maintain avacuum therein, tracks in said tank, a wheeled tube winding mechanismwithin said tank supported on said tracks, and supplemer tal tracksexterior to the tank outwardly upon. which the said wheeled tube windingmechanism is adapted to be drawn when the closure is removed.

9. A machine for the purpose set forth comprising an air tight tank withmeans to produce and maintain a vacuum therein, and provided with a.removable wall and with an interior track, a tube winding mechanism insaid tank, comprising a wheeled purpose set forth frame supported onsaid track, a rotative mandrel on said frame, an insulating compoundreceptacle supported on said frame, means to guide a sheet of insulatingmaterial through the insulating compound, means to wind it on saidmandrel, and supplemental tracks exterior to the tank outwardly uponwhich the frame is adapted to be drawn.

10. A machine for the purpose set forth comprising an air tight tankwith means to produce and maintain a vacuum therein, andprovided with aremovable wall and with an interior track, a tube winding mechanism insaid tank, comprising a wheeled frame supported on said track, arotative mandrel on said frame, an insulating compound receptaclesupported on said frame in such position that a forming tube ispartially submerged in the compound, means to guide a sheet ofinsulating material through the insulating compound, means to wind it,on said mandrel, supplemental tracks exterior to the tank outwardly uponwhich! the frame is adapted to be drawn, said tube winding mechanismbeing provided with a self-contained operating motor supported on saidframe, whereby the tube may be rotated in the insulating compound afterthe frame has been withdrawn upon said supplemental track.

11. In a machine for the purpose set forth, v

assembling means for superposing impregnated sheets to constitute amulti-ply insulating element and means for subjecting the sheet to theinfluence of a high potential electro-static discharge prior to theassembling operation.

In a machine for the purpose set forth, means for impregnating a sheetwith an insulating compound, means for winding the impregnated sheetinto a tube, and means for subjecting the impregnated sheet to the"influence of a high potential electro-static discharge prior to thewinding operation.

13. In a machine for the purpose set forth, means for impregnating asheet with an insulating compound, means for winding the impregnatedsheet into a tube, means for scrapin excess of insulating compound fromtie sheet and means for subjecting the scraped sheet to the influence ofan electro-static discharge.

14. In a machine for the purpose set forth, assembling means forsuperposing impregnated sheets to constitute a multi-ply insulatingelement and means for subjecting the sheet to the influence of a highpotential electro static discharge prior to the assembling operation,combined with means for subjecting the sheet to a high vacuum during thewinding operation.

15. A machine for the purpose set forth comprising a receptacle tocontain a liquid insulating compound, a mandrel mounted to rotatepartially in the receptacle, with means to rotate it, and to feed asheet of insulating material through the compound and to reel it on saidmandrel, arms pivoted to the frame and swingable toward and from themandrel, a smoothing roller carried by the arms, with means toyieldingly press it against the sheet at the line of laying the sheet onthe forming tube on the mandrel, a metal roller .over which said sheetpasses on its way to said smoothing roller, said metal roller beingincluded in a high potential electric open circuit, and the sheetadjacent to said metal roller being subjected to an electrostaticdischarge between said roller and a grounded metallic part of thewinding mechanism.

16. A machine for the purpose set forth comprising a receptacle tocontain a liquid insulating compound, a mandrel mounted to rotatepartially in the receptacle, with means to rotate it, and to feed asheet of insulating material through the compound and reel it on saidmandrel, arms pivoted to the frame and swingable toward and from themandrel, a smoothing roller carried by the arms,

. with means to yieldingly press it against the sheet at the line oflaying the sheet on the forming tube on the mandrel, a metal roller overwhich said sheet passes on its way to said smoothing roller, said metalroller being included in a high potential electric open circuit, thesheet adjacent to said metal roller being subjected to an electrostaticdischarge'between said roller and a grounded metallic part of thewinding mechanism, and scraper bars carried also by said swinging armsbetween the smoothing roller and said metallic roller for scrapingexcess insulating compound from said sheet.

17. Amachine for the purpose set forth comprising means for impregnatingthe sheet, means for superposing the impregnated sheet in layers toconstitute a multiply insulating element, means to subject the sheetbefore it is impregnated to a partial vacuum and means whereby theformed element is subjected to a pressure considerably higher than thepressure under which the element is formed.

18. A machine for the purpose set forth comprising means to support asheet roll, means to assemble the sheet in superposed layers toconstitute a multi-ply insulating element, means between the support forthe roll and the assembling means to impregnate the sheet with aninsulating compound and means whereby the sheet before it passes to theimpregnating means, and the insulating element after it has been formed,may be subjected to varying air pressures.

19. A machine for the purpose set forth comprising an air tight tankwith means to produce and maintain a vacuum therein during theimpregnation and assembling operation, mechanism within the tank forassembling thin sheets to constitute a multi-ply insulating element,means to apply pressure to the sheet as the layers are assembled in the.

the vacuum prior to the setting of the insulating compound whereby themulti -ply element sets or hardens under atmospheric pressure.

20. A machine for the purpose set forth comprising an air tight tank andan insulating compound receptacle therein, a mandrel onwhich to form atube from a continuous sheet while the forming tube is partiallysubmerged in the compound in said receptacle, means to maintain apartial vacuum within the tank during the tube forming operation, meansto release the Vacuum and means to turn the mandrel and formed tube inthe compound while said tube sets or hardens.

21. A machineifor the purpose set forth comprising an air tight tankprovided with a removable closure, a mechanism within the tank forassembling thin sheet layers to constitute a multi-ply insulatingelement, means for impregnating the sheet layers with an insulatingcompound prior to the assembling operation and a supporting frame forthe assembling and impregnating means movable into and out of the tank.

22. A machine for the purpose set forth comprising a tank provided witha removable closure, a rotating mandrel, means to support a roll ofsheet material within the tank and to wind it on said mandrel, areceptacle for liquid insulating compound through which the sheet ispassed on its way to said mandrel, and a supporting frame for saidmandrel, roll and receptacle movable into and out of the tank.

23. A machine for the purpose set forth, comprising an air tight tank,means to produce and maintain a partial vacuum therein, a receptacle forliquid insulating compound in said tank, a tube forming mandrel alsowithin said tank, means" Within the tank to support a roll of sheetmaterial andto direct'it through said receptacle and to the mandrel, anda supporting frame for said sheet supporting means, said receptacle andsaid mandrel movable into and out of the tan r.

24:. A machine for making insulating elements comprising an airtighttank, with means for producing a vacuum therein, means to support aroll of sheet material, a mandrel on which the impregnated sheet iswound, means for directing a sheet through a bath of insulating materialand for directing the impregnated sheet'to the mandrel without exertinga squeezing pressure ire thereon of a nature to expel" the insulating13G material from the body of the sheet and means at the mandrel to freethe surface of the sheet from free fluid, the sheet supporting, thewinding and the fluid freeing means, being all contained within thetank.

25. A machine for making insulating elements comprising means forassembling a plurality of layers or lamime of a sheet into an element,means to impregnate the sheet with an insulatingcompound prior to theassembling operation, and means to subject all parts of the sheet priorto the impregnating operation to a Vacuum.

In testimony, that I claim the foregoing as my invention I affix mysignature in the 15 presence of two Witnesses, this 26th day ofFebruary, A. D. 1915.

CHESTER H. THORDAR-SON.

